An Australian man, sentenced to 20 years in jail for the murder of a Bulgarian student in 2007, has lost his final appeal as the country's supreme court of appeal upheld his sentence.

Jock Palfreeman will now have to serve out the remainder of his jail term.

The Australian was initially sentenced in December 2009 for stabbing to death 20-year-old Bulgarian student Andrey Monov and wounding another man in a drunken street brawl in the capital Sofia.

Palfreeman pleaded not guilty to the crime, claiming self-defence.

While he admitted to drinking alcohol before the fight, the now 24-year-old said he only became involved by chance when he ran to help a Roma man who was being beaten by a large group of drunken Bulgarians.

Conflicting witness reports were however deemed insufficient by the court to confirm his claims.

After he was found guilty, Palfreeman launched an appeal with the Sofia appeals court, hoping to have the ruling overturned or at least his jail term reduced.

The prosecution meanwhile filed its own appeal, demanding life in prison without parole.

The Sofia appeals court upheld Palfreeman's 20-year jail sentence in February, which was confirmed by the supreme court of appeal on Wednesday.

The court also ordered Palfreeman to pay Monov's family 450,000 leva ($364,000) in damages.